Contact lens wearers usually insert and remove their contact lenses manually. With Rigid Gas Permeable (RGP) and the new hybrid contact lenses this task can be more complicated. Hybrid lenses are designed to correct atypical vision problems and have irregular thicknesses, often a rigid central zone and softer peripheral zone. These types of specialized contact lenses are often larger in diameter and can form a stronger adherence to the eye surface, which can make them difficult to remove. Inserting and removing contact lenses can have other ergonomic limitations, given that it is a maneuver that typically requires manual dexterity, coordination, and stability. People for whom inserting and removing RGP and hybrid contact lenses with their fingers can be a difficult task includes seniors, children, superior-limb handicapped individuals, those with long fingernails, or anyone lacking the necessary manual dexterity or stability.
A variety of lens manipulators with suction cups have been developed to manipulate specialized contact lenses, but many are not equally effective for both insertion and removal of a contact lens. If the suction cup of the lens manipulator can provide sufficient suction on contact with the contact lens to facilitate removal, that same force may not release the contact lens when the suction cup is retracted. Likewise, if suction or adherence is sufficient to facilitate insertion and easy release, then the suction cup may not exert sufficient suction to be effective for removal.
Some lens manipulators utilize suction cups that rely on “passive” vacuum force, wherein the vacuum force in the cup depends upon the volume of air displacement under the concave surface of the suction cup. Air displacement can be accomplished by either pressing the suction cup onto a surface to compress the suction cup, or by pressing/releasing a flexible or pliant bulb attached to the suction cup. Either method results in a decrease in pressure under the suction cup. These techniques, usually manually controlled, may not provide sufficient control over the vacuum force that the cup can exert on the contact lens and the eye. Thus, the amount of pressure under the suction cup cannot be precisely or consistently regulated. Further, if the contact lens is stuck to the eye and cannot be removed normally, it can be difficult to disengage the already attached suction cup from the contact lens.
Other lens manipulators for contact lens insertion and extraction can provide “active” vacuum or positive pressure with the use of a pump, such as, for example, the CLIARA device disclosed in U.S. Published Application No. 2015/0265467. These types of devices can require specific configurations of suction cups to facilitate the formation and release of vacuum force within the cup.
Surface tension, Van der Waal's forces, hydrophilic/hydrophobic interactions, and other factors can affect the surface interaction between the contact lens and the suction cup. Certain materials, surface finishes, textures, additives or coatings, and other substances can make the suction cup surface “sticky,” causing it to adhere to the lens surface, independent of the vacuum pressure. A suction cup with a “sticky” surface can be beneficial for contact lens extraction, but inhibit contact lens insertion by not releasing the lens once engaged with the eye. The opposite can also be true, where a non-sticky surface can be beneficial for insertion, but can inhibit extraction.
There is a need for a suction cup that addresses the limitations of previously known suction cups on such devices, with regard to insertion and removal of contact lenses. Ideally, such a suction cup can be used with a lens manipulator that can aid in inserting and removing contact lenses with more control over the amount of suction force. Such a device can, ideally, reduce the amount of manual dexterity and coordination required to remove and insert specialized contact lenses, and inhibits undesirable contact with the cornea or sclera of the eye. It can also be advantageous if the device can be released by a user through activation of a quick-release mechanism or to release the contact lens automatically if excessive extraction force is applied to the contact lens.